Hydraulic locking cylinder for locomotive reversing gear



Sept. 26, 1950 J. HADFIELD HYDRAULIC LOCKING CYLINDER FOR LOCOMOTIVEREVERSING GEARS 3 Sheets-Sheet 1 Filed July 31, 1945 Ins en'To/t J.HADFIELD HYDRAULIC LOCKING CYLINDER FOR Sept. 26,1950

LOCOMOTIVE REVERSING GEARS 3 Sheets-Sheet 2 Filed July 31. 1945'iiiiljk- 1 v VIIvrlldltrllllllrlllillfr Mu s a n 3 e 4 2 m 3 KW S. H v a\,,,,,,./A I? RI: m n 3 \b/ L I\ W MV/// I, l W Li 5 Fs Rm 7 v "\h A IGmum m m FG 0mm m "1mm JCH um U0 mm m Patented Sept. 26, 1950 HYDRAULICLOCKING CYLINDER FOR LOCOMOTIVE REVERSING GEAR James Hadfield, Romiley,England Application July 31, 1945, Serial No. 607,962 In Great BritainOctober 7, 1944 This invention relates to reversing gear for steamlocomotives of all types where the engine is reversed by means of apower operated reversing gear comprising a power cylinder operated bysteam, compressed air or other suitable medium and a hydraulic cylinderfor the purpose of locking the gear in any desired position.

Apparatus of this type as hitherto constructed has suffered from twomain and complementary defects. The hydraulic locking cylinders havebeen difficult to fill completely so as to ensure that all air isevacuated in the filling process and, moreover, even when initiallyfilled completely, difficulties have been experienced in maintaining thehydraulic cylinders full and free from air since leakage is, to someextent, inevitable and in the normal arrangements at present known anyliquid which leaks out is replaced by air. The result is that a positivelock is not provided and thegear creeps.

The object of the present invention is to remedy these defects so as toensure positive locking for any position of the reversing gear and theprimary feature of the invention is the provision in a power operatedreversing gear, of a pump automatically operating to replace any liquidwhich leaks from the hydraulic cylinder, whereby the cylinder havingonce been filled is maintained full under all conditions.

A further complementary feature of the invention is the method ofinitially filling the hydraulic lockin cylinder according to which thefilling operation is effected by means of a pump and takes place fromthe bottom of the cylinder so that the air in the cylinder is dischargedas the liquid level in the cylinder rises. Thus, if the filling from thebottom ofthe cylinder is continued until there is an overflow of the oilor other liquid from vents at the top, a completely filled cylinder freefrom air results.

The essential factors necessary for the practical success of theinvention may be stated as the provision of means whereby the hydrauliclocking cylinder can be expeditiously and completely filled, meanswhereby the hydraulic system will be instantly and automaticallyreplenished should any liquid escape therefrom, and means whereby thetwo ends of the hydraulic cylinder can be'interconnected one with theother, or completely isolated one from the other.

The invention consists broadly of reversing gear for steam locomotivescomprising a power cylinder or unit for efiecting the movements 2Claims. (01. 121-40),

, 2 of the gear under'control from the engine cab, and a hydrauliclocking cylinder for locking the gear in its set portions, wherein asupply of liquid under pressure is provided and conducted to thehydraulic locking cylinder on both sides of its piston, whereby on theoccurrence of leakage from the hydraulic lockin cylinder such liquid asleaks out is automatically replaced from said supply.

In order that the invention may be clearly understood and carried intopractice reference is hereby made to the accompanying drawings, wherein:

Figure lis a side elevational View showing the general arrangement ofthe invention applied to a locomotive reversing gear of known generalcharacter;

Figure 2 is a section on the line 2--2 of Figure 1;

Figure 3 is a sectional side elevation of the pump shown at the righthand side of Figure 1;

Figure 4c is a plan and Figure 5 is an end view of Figure 3;

Figure 6 is a, sectional view of the hydraulic locking cylinder showingone form of the hydraulic control valve which may be employed;

Figure '7 is a sectional end view thereof; and

Figures 8 and 9 are views similar to Figures 6 and 7 illustrating analternative form of hydraulic control valve.

Referring to these drawings Figure 1 shows the general arrangement of apower operated reversing gear which consists of a power operated unit A;hydraulic locking cylinder B and control lever C connected at D to 'anoperating lever E in the drivers cab. The control lever C is alsoconnected at F: through link G to the crosshead H on the reverser pistonrod and at J by means of links connected to levers on the powervalve Kand hydraulic valve L respectively. There are, oicourse, otherknown'arrangements of power operated reversing gears having hydrauliccylinders but the function of the hydraulic locking cylinder in allarrangements is to lock the gear in any desired position.

In Figures 3, 4 and 5 theautomatic pump which is the characterisation ofthe present invention and is indicated by the letter P in Figure 1 isshown in detail. I

This automatic pump consists of a plunger M loaded by a spring N andcapable of operation by a hand lever O.

On operating the hand lever 0, liquid is drawn from the reservoir Pthrough the non-return valve Q into the pump chamber R.

The plunger M under load from the spring N exerts a pressure on theliquid which is forced through the non-return valve S and then throughthe pipe T and the non-return valves U (Figure 6) to the two ends of thehydraulic cylinder B.

The non-return valves U are shown in Figure 6 as being of the ball typebut it will be understood that any other form of non-return valve may beused.

An indicator may be provided on the pump casing suitably marked to showwhether the pump plunger M is in the fully charged position orotherwise. The pump unit may be located in the drivers cab or in anyother convenient position.

For the initial filling of the hydraulic cylinder the air vent plugs V(Fig. 6) are first removed and the hydraulic control valve is placed inthe open" position. The pump reservoir P is filled with a suitableliquid (usually oil or water) and the pump is operated until the liquidentering the cylinder B by wa of the pipe T and branch pipes T and Tflows through the vent holes on the top of the hydraulic cylinder. Thepump reservoir must be replenished from time to time as may be necessaryuntil this preliminary filling operation is completed.

The vent plugs V are then replaced and the pump reservoir P is refilledand the charging lever moved into the fully charged position.

Should any leakage occur thereafter through the glands of the piston rodof the hydraulic cylinder or elsewhere, liquid, under pressure exertedby the pump plunger M acting under the load of the spring N, will flowinto the hydraulic cylinder thus replenishing the cylinder with liquidand preventing the ingress of air which would otherwise take place.

The only attention required by the apparatus under running conditions isto maintain the level of the liquid in the reservoir P and to moveoccasionally the hand lever O to the fully charged position.

In order to permit of the interconnection or isolation of the ends ofthe hydraulic cylinder 13 the hydraulic cylinder is provided with animproved type of hydraulic control valve as shown in Figure 6. Thisvalve consists of two spring loaded poppet valves W which are operatedby a cam X through intermediate rockers Y, this arrangement ensuringthat the two ends of the hydrau'l'ic cylinder are positively isolatedwhen the cam X is in the shut position. It will be obvious that thehigher the pressure occurring in the hydraulic cylinder by the action ofthe locomotive valve gear the more tightly closed become the valves W,thus eliminating all tendency for the reversing gear to creep.

An alternative type of hydraulic control valve is shown in Figures 8 and9. This consists of a cylindrical piston valve Z sliding in a liner AAand capable of being operated by the lever BB.

Suitable ports are provided in the valve and liner, so arranged thatdisplacement of the valve in either direction away from the centralclosed position will permit the liquid to flow from one end of thehydraulic cylinder to the other thus permitting the reversing gear tomove until the hydraulic valve is returned to the central or closedposition.

Provision will preferably be made for adjusting the operating speed ofthe reverser by means,

for example, of a throttling plug indicated at CC and the function ofwhich is to regulate the rate of flow of liquid passing from one side ofthe hydraulic piston to the other. Adjustment is made by modifying thedimensions of that part of the throttling plug which projects into theport of the hydraulic cylinder.

I claim:

1. Reversing gear for steam locomotives comprising a power unit having amoving member for imparting the required movement to the gear, ahorizontally positioned hydraulic locking cylinder, a piston slidable insaid locking cylinder and coupled to the moving member of the powerunit, a valve housing atop said cylinder, valve means in said housing, apassageway interconnecting opposite ends of said cylinder through saidvalve means, said valve means comprising a pair of oppositely disposedaligned valve seats, a pair of valve members adapted to engage the outerfaces of said valve seats and close off said passageway, springsnormally holding said valve members in engagement with said valve seats,a pair of rocking levers disposed between said valve seats and eachengaging one of said valve members, and a cam disposed between saidrocking levers for engaging them and moving them apart, whereby todisengage the valve members from the valve seats to open saidpassageway, closable vent means adjacent the top said valve housing, ahydraulic fluid inlet adjacent the bottom of each end of said cylinder,means for supplying hydraulic fluid to said inlets, and meansmaintaining said fluid under pressure.

2. Reversing gear for steam locomotives comprising a power unit having amovable member for imparting the required movement to the gear, ahydraulic locking cylinder, a piston slidable within said cylinder andcoupled to the movable member of the power unit, a hydraulic fluid inletto each end of said cylinder, means supplying hydraulic fluid to saidinlets, means maintaining said fluid under pressure, means forming apassageway interconnecting opposite ends of said cylinder, valve meansin said passageway controlling the flow of fluid therethrough, saidvalve means being biased to closed position by means including thepressure exerted on said fluid by said pressure maintaining means, andmeans actuated simultaneously with the motion of said movable member foropening said valve means to thereby place both ends of said lockingcylinder in communication with one another.

JAMES HADFIELD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 708,332 Ennor Sept. 2, 19021,094,243 Pilling Apr. 21, 1914 1,248,357 McEntire Nov. 27, 19171,307,281 Wallace June 17, 1919 1,954,417 Lentz Apr. 10, 1934 2,397,270Kelly Mar. 26, 1946 FOREIGN PATENTS Number Country Date 8,274 GreatBritain of 1915 216,596 Great Britain June 5, 1924

